The present invention relates to laundry substrate articles, yielding excellent removal of particulate and greasy/oily soils, which contain mixtures of specific types of nonionic and cationic surfactants. These articles are formulated so as to increase the rate at which the nonionic/cationic surfactant mixture is released into the washing solution, thereby maximizing the cleaning benefit obtained, and to minimize the bleeding of the surfactant components from the substrate material.
The convenience and efficiency which is obtained by incorporating premeasured amounts of laundry detergent compositions into substrate articles, for direct addition to the automatic washing machine, are well known. Examples of such articles are taught in U.S. patent application Ser. No. 781,378, Flesher et al, filed Mar. 25, 1977; U.S. Pat. No. 4,095,946 Jones et al, issued June 20, 1978; U.S. Pat. No. 4,118,525, Jones, issued Oct. 3, 1978; and U.S. Pat. No. 4,113,630, Hagner et al, issued Sept. 12, 1978, all of the disclosures of which are incorporated herein by reference. In addition, U.S. patent application Ser. No. 811,220, Murphy, filed June 29, 1977, and U.S. patent application Ser. No. 811,221, Cockrell, filed June 29, 1977, both of which are incorporated herein by reference, disclose detergent compositions, containing mixtures of specifically defined nonionic and cationic surfactants, which yield outstanding removal of particulate and greasy/oily soils. It would be very desirable to combine the outstanding cleaning performance of these detergent compositions with the convenience of the substrate articles.
In order to combine these two technologies, several problems must be overcome. It is necessary to provide for rapid and complete release of the surfactant mixture from the substrate into the laundry solution, in order both to maximize the cleaning benefits obtained during the relatively short automatic laundering cycle, and to minimize waste of the surfactant components. Further, it is desirable to minimize the bleeding of the surfactant mixture, particularly the nonionic component, through the substrate sheets, which may occur during storage of the articles. It has now been found that the release of the nonionic/cationic surfactant mixtures into the laundry solution can be greatly increased by using the specific types of solubilization aids defined herein. It has further been found that the bleeding of the detergent components can be controlled by including the specific materials, having the required particle sizes, disclosed herein in the substrate articles.
It is, therefore, an object of the present invention to define a laundry substrate article providing excellent cleaning and which may also provide fabric care benefits, such as static control, fabric softening, and dye transfer inhibition, to the laundered fabrics.
It is another object of the present invention to provide a substrate article having improved release of its active components into the wash solution.
It is a further object of the present invention to provide a laundry substrate article wherein the bleeding of active components through the substrate sheets is minimized but which also exhibits proper release of the active components into the washing solution.
It is yet another object of the present invention to provide a process for laundering fabrics using the substrate articles described herein.